Reviewing two versions of the same asset usually means flipping back and forth between tabs, trying to hold the differences in your head. It's a lot of work for something as simple as "which one is better?" That's where side-by-side comparison comes in! You can line up two assets in a single window, play them together, and leave comments on each — all without losing your place.
Figure 1: Comparing two assets side by side
Starting a Comparison
To get started, simply select two assets in any folder, search result, or Catalog view. Then click 'Compare files' in the blue action bar, or right-click and choose 'Compare files'. The first asset you selected loads on the left, and the second loads on the right:
Figure 2: Selecting two files to compare
Please note that both assets need to be the same type — either two videos or two images. You'll also need view access to each asset; comparison doesn't grant any extra access.
Getting to Know the Window
The comparison window opens full-screen over your current view. Closing it brings you right back to where you were.
Each panel is color-coded to keep things clear: the left panel is blue, and the right is orange. That color carries through to each side's comments, timecodes, and scrubber, so you always know which asset you're working on. One panel is always focused — that's the one your controls, keyboard, and audio apply to. The focused panel is highlighted, and focus follows your attention: click a panel, press '1' or '2', or interact with a panel's comments to shift focus to it.
Please note that only the focused panel plays audio. The other side is muted, and switching focus switches the sound. If you'd like to flip the two sides, click 'Swap sides' in the toolbar or press Shift+S. This is a visual reorder only — playback, zoom, comments, and audio all stay exactly where they were.
Playing Back Your Assets
A single shared control bar drives whichever panel is focused. You'll find play/pause, frame stepping, ±3-second jumps, playback rate, volume, a scrubber with filmstrip, and timecode — all in the familiar layout from the standard preview.
The easiest way to A/B is to focus one asset and position it, then press '1' or '2' to switch to the other.
Figure 3: Previewing Side-by-Side
Linking the Two Playheads
Once you've positioned each asset where you want it, click 'Link playhead' in the toolbar (or press Shift+P) to move them together. Linking captures the gap between the two playheads and holds it. So if the left is at 5 seconds and the right is at 12 seconds, linking locks in a 7-second offset, and both players will move together from there.
Please note that linking doesn't align the two assets to a matching moment — it holds whatever gap you've set. Position each asset first, then link. You can unlink at any time to navigate independently, then re-link at a new sync point as you work through the material. Each time you re-link, a fresh offset is captured from the current positions.
Figure 4: Linking the two playheads
Linking Pan and Zoom
To compare a specific detail across both assets, click 'Link Pan/Zoom' in the toolbar (or press Shift+Z). Zoom or drag one panel, and the other follows the same movement, up to 8× magnification. This works for both video and image pairs, so you can hold two videos at the same zoom level on the same region while they play. Fit-width and fit-height recenter each panel independently:
Figure 5: Linking pan and zoom
Commenting on Each Side
Each panel has its own comment panel, and both are live at the same time. Commenting works the same way it does in the standard preview — you can add time-coded comments, draw spatial annotations, reply, resolve, delete, follow, and search.
- Time-coded comments anchor to that asset's playhead. Clicking a comment seeks that panel to the right spot (and the partner panel too, when linked).
- Spatial annotations (pins and freehand) belong only to the asset they were drawn on, and work on images and video frames.
Please note that while you're drawing an annotation on one panel, the other is locked so both can't be drawn on at once. Starting an annotation also resets both panels to 100% zoom, so you have a full frame to draw on. Filter, sort, search, and follow settings all work independently for each side. Please note that commenting isn't available when comparing assets from a Catalog:
Figure 6: Commenting on each side
Keyboard Shortcuts
If you prefer to keep your hands on the keyboard, these shortcuts work anywhere in the comparison window:
| Key | Action |
|---|---|
| Space or K | Play / pause |
| Left / Right, or , / . | Step ∓1 frame |
| Shift + Left / Right | Jump ∓3 seconds |
| J / L | Playback rate down / up |
| M | Mute the focused panel |
| 1 / 2 | Focus left / right panel |
| Shift + S | Swap sides |
| Shift + C | Toggle comments |
| Shift + P | Link / unlink playheads |
| Shift + Z | Link / unlink pan and zoom |
| Escape | Cancel an annotation |
A Few Things to Keep in Mind
- Comparison works with two videos or two images. Audio files, documents, and mixed pairs aren't supported.
- You can compare exactly two assets at a time.
- Only the focused panel plays audio — there's no way to hear both at once.
- Comparisons open in a full-screen window rather than a page with its own address, so they can't be bookmarked or shared as a link.
- Comparison is available in the main application on desktop browsers only. It isn't available in Mediabox, on mobile or tablet, or in the Premiere Pro or DaVinci Resolve panels.
- Playing two assets at once uses more of your browser and network than a normal preview, so playback may feel less smooth on lower-spec machines or slower connections.
For any additional questions, please reach out to the Ci Customer Success Team by submitting a request here in the Help Center.